W3School TIY Editor
W3School 在线教程
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暗黑模式
运行代码
<html> <body> <form> Male: <input id="male" type="radio" name="Sex" value="Male" /> <br /> Female: <input id="female" type="radio" name="Sex" value="Female" /> </form> <script type="text/javascript"> document.getElementById('male').focus(); </script> </body> </html>